Push to connect conduit fitting with ferrule

ABSTRACT

A push to connect fitting includes a body member adapted to receive a conduit end, a conduit comprising a first end that can be axially inserted into the body member and a conduit gripping device attached to an exterior surface of the conduit, and a retainer that retains the conduit in place when said conduit is fully inserted into the body member. Additional embodiments include providing a seal with the fitting that seals the exterior surface of the conduit, an optional load retaining sleeve for the conduit gripping device, and an optional gimbal. The push to connect aspect may be realized in the form of a single action unthreaded mechanical connection.

RELATED APPLICATION

This application is a continuation of U.S. Ser. No. 15/992,125, filed onMar. 15, 2018, granted as U.S. Pat. No. 10,584,820 on Mar. 10, 2020,which claims priority to U.S. Ser. No. 13/898,828, filed on Apr. 11,2013, granted as U.S. Pat. No. 9,958,100 on May 1, 2018, which claimspriority to U.S. national phase of entry of PCT/US2011/56259, with aninternational filing date of Oct. 14, 2011 which claims the benefit ofprovisional U.S. Application Ser. No. 61/393,492 filed on Oct. 15, 2010for PUSH TO CONNECT CONDUIT FITTING, the entire disclosures of which arefully incorporated herein by reference in their entirety.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure relates to fittings or mechanical connections formetal conduits such as metal tube and pipe. More particularly, thedisclosure relates to fittings that can be quickly assembled with a pushto connect action.

BACKGROUND OF THE DISCLOSURE

Fittings are used in gas or liquid fluid systems to provide a fluidtight mechanical connection between a conduit and another fluid flowdevice, such as another conduit, a flow control device such as a valveor regulator, a port and so on. A particular type of fitting commonlyused is known as a flareless fitting that uses one or more conduitgripping devices such as ferrules, for example, to provide the conduitgrip and seal functions. Such fittings are popular as they do notrequire much preparation of the conduit end, other than squaring off andde-burring. High performance conduit fittings typically involve athreaded connection wherein the fitting is pulled-up or tightened byrelative rotation of turns and partial turns between two threaded matingcomponents.

SUMMARY OF THE DISCLOSURE

In accordance with an embodiment of one or more of the inventionspresented in this disclosure, conduit fitting concepts are disclosedthat facilitate assembly by using a push to connect action or method. Inone embodiment, a conduit fitting assembly facilitates a single actionpush to connect mechanical connection. In exemplary embodiments, thefitting may be realized with a non-threaded mechanical connection.Preferably, although not required, a generally cylindrical conduit endmay be inserted into an un-tightened or loosely assembled fittingassembly and retained in place as a final or completed connection. In aparticular embodiment, a separate tool may be used to allow the conduitto be removed from the completed assembly without complete separation ofthe constituent parts, but in an alternative embodiment for the tool,the tool may be integrated with a conduit retention mechanism. In otherembodiments, one of the fitting components provides structure by whichthe conduit may be removed without complete separation of theconstituent parts. In the exemplary embodiments, a mechanical connectionmay be made to a conduit end without requiring any shaping, forming ormachining of the conduit other than optionally the usual end facing anddeburring. The exemplary embodiments herein also exhibit excellentperformance characteristics as to pressure, seal and fatigue resistancefrom vibrations and stress applied to the conduit. As such, the fittingconcepts disclosed herein are well suited for many differentapplications, including automotive applications, that may endure longperiods of vibration and stress on the conduit, but with the fittingbeing able to seal several thousand pounds per square inch of gaspressure over typical operating temperatures of about −40° F. or lowerto about 250° F. or higher.

In still further embodiments, intrinsic gauging features may optionallybe provided with the conduit fitting assembly to provide a visual ortactile indication to the assembler whether the fitting assembly is in aloosened or tightened condition.

These and other embodiments of various inventions disclosed herein willbe understood by those skilled in the art in view of the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates in an exploded view a first embodiment of one or moreof the inventions herein, in longitudinal cross-section;

FIG. 2 is the assembly of FIG. 1 with a conduit captured in theassembly;

FIG. 3 is the assembly of FIG. 2 under system pressure;

FIG. 4 is the assembly of FIG. 3 with a tool inserted to allow conduitremoval;

FIG. 5 is another embodiment of a push to connect fitting assembly shownin longitudinal cross-section and in a preassembled position;

FIG. 6 is the assembly of FIG. 5 in a fully assembled position;

FIG. 7 is the assembly of FIG. 6 with a tool inserted to allowdisassembly of the push to connect fitting;

FIG. 8 is another embodiment of a push to connect fitting assembly shownin longitudinal cross-section and in a preassembled position;

FIG. 9 is an embodiment of a positioning sleeve used in the fitting ofFIG. 8;

FIG. 10 is the assembly of FIG. 8 in a fully assembled position;

FIG. 11 is the assembly of FIG. 10 with a removal tool operated to adisassembly position;

FIGS. 12 and 13 illustrate alternative embodiments of various featuresin the first three embodiments;

FIGS. 14 and 15 illustrate additional alternative embodiments, showing asingle ferrule with a nut for conduit retention, in a fully assembledposition.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Although the exemplary embodiments herein are presented in the contextof mechanical connections for rigid conduits, for example a stainlesssteel tube fitting, the inventions herein are not limited to suchapplications, and will find use with many different metal conduits suchas tube and pipe as well as different materials other than 316 stainlesssteel, and may also be used for liquid or gas fluids. Although theinventions herein are illustrated with respect to a particular design ofthe conduit gripping devices and fitting components, the inventions arcnot limited to use with such designs. The inventions may be used withtube or pipe, so we use the term “conduit” to include tube or pipe orboth. We do not intend that the term conduit be limited as to anyparticular length, use or configuration; for example, a conduit may be atube stub or other metal jacket or sleeve type component used to providea fitting connection. We generally use the terms “fitting assembly” and“fitting” interchangeably as a shorthand reference to an assembly offitting components along with one or more conduit seal and grippingdevices. The concept of a “fitting assembly” thus may include anassembly of the parts onto a conduit, either in a loosely assembled orfully assembled tightened position; but the term “fitting assembly” isalso intended to include an assembly of parts together without aconduit, for example for shipping or handling, as well as theconstituent parts themselves even if not assembled together. We also usethe term “fitting remake” and derivative terms herein to refer to afitting assembly that has been at least once tightened or completelyconnected, loosened, and then re-assembled to another completelyconnected position. Remakes may be done with the same fitting assemblyparts or may involve the replacement of one of more of the parts of thefitting assembly. Reference herein to “outboard” and “inboard” are forconvenience and simply refer to whether a direction is axially towardsthe connection (inboard) or away from the connection (outboard),referenced to the central longitudinal axis X of the fitting assembly.All references herein to “radial” and “axial” are referenced to the Xaxis except as may otherwise be noted. Also, all references herein toangles are referenced to the X axis except as may otherwise be noted. Weuse the term “conduit end” to refer to an end portion of a conduit. By“intrinsic gauge” we mean a structure that provides an indication thatpull-up of a fitting is complete, without the need for a separate gaugetool or device.

We use the term “unthreaded mechanical connection” in reference to amechanical connection between a conduit and another component using asingle action movement that completes conduit retention with thecomponent without using a second action, for example, a threadedengagement. In other words, a traditional tube fitting that is not apush to connect fitting typically involves a first action of insertingthe conduit into the fitting assembly with the fitting in a finger tightposition, and then a second action of tightening the threaded nut andbody together using torque applied to the threaded connection tocomplete the pulled up assembly. The term “unthreaded mechanicalconnection” is not intended to exclude additional optional structureassociated with the mechanical connection that may be threaded, butrather contemplates any mechanical connection for a conduit that doesnot require a threaded connection to effect the retention of the conduitwith the connected component. We use the term “single action” to referto a mechanical connection that is made with a single movement, forexample an axial insertion. Another example of a single actionconnection or fitting is a push to connect assembly by inserting aconduit axially into another component. As used herein, the term “singleaction” is intended to include manual assembly as well as assembly witha tool.

While various inventive aspects, concepts and features of the inventionsmay be described and illustrated herein as embodied in combination inthe exemplary embodiments, these various aspects, concepts and featuresmay be used in many alternative embodiments, either individually or invarious combinations and sub-combinations thereof. Unless expresslyexcluded herein all such combinations and sub-combinations are intendedto be within the scope of the present inventions. Still further, whilevarious alternative embodiments as to the various aspects, concepts andfeatures of the inventions—such as alternative materials, structures,configurations, methods, devices and components, alternatives as toform, fit and function, and so on—may be described herein, suchdescriptions are not intended to be a complete or exhaustive list ofavailable alternative embodiments, whether presently known or laterdeveloped. Those skilled in the art may readily adopt one or more of theinventive aspects, concepts or features into additional embodiments anduses within the scope of the present inventions even if such embodimentsare not expressly disclosed herein. Additionally, even though somefeatures, concepts or aspects of the inventions may be described hereinas being a preferred arrangement or method, such description is notintended to suggest that such feature is required or necessary unlessexpressly so stated. Still further, exemplary or representative valuesand ranges may be included to assist in understanding the presentdisclosure, however, such values and ranges are not to be construed in alimiting sense and are intended to be critical values or ranges only ifso expressly stated. Moreover, while various aspects, features andconcepts may be expressly identified herein as being inventive orforming part of an invention, such identification is not intended to beexclusive, but rather there may be inventive aspects, concepts andfeatures that are fully described herein without being expresslyidentified as such or as part of a specific invention, the inventionsinstead being set forth in the appended claims. Descriptions ofexemplary methods or processes are not limited to inclusion of all stepsas being required in all cases, nor is the order that the steps arepresented to be construed as required or necessary unless expressly sostated.

With reference to FIGS. 1-4 and initially FIG. 1, a first embodiment ofone or more of the inventions is presented. In this example, a conduitfitting assembly 10 for tube or pipe conduit C may include a conduitreceiving component 12. We also refer to the conduit receiving component12 as a body wherein the body 12 receives a conduit end portion C1.Although we use the common term of body as a convenience, those skilledin the art will appreciate that the inventions are not limited toapplications wherein such terminology may be used to describe the part.The body 12 may be a stand-alone component as illustrated or may beintegral with or integrated or assembled into another component orassembly such as, for example, a valve, a tank or other flow device orfluid containment device. The body 12 may have many differentconfigurations, for example, a union, a tee, an elbow and so on to namea few that are well known in the art. The body 12 herein is alsocommonly known in the art as a port body or female port because itsentire structure can be although need not be recessed in or formed inanother structure (for example, a valve body or a cylinder), and amechanical connection for a conduit end can still be made therewith.

The fitting embodiments herein will find particular application in theautomotive industry; however, they may be used anywhere there is a needfor fluid pressure containment. As an example, the inventions herein maybe used to realize an automotive fitting for containing rated gaspressures (for example, for methane) of about 3000 to about 3500 psiwith rated performance as high as 5000 psi or greater. The fittingsherein may be scaled to accommodate conduits such as nominal outsidediameters of ⅛ inch or less up to and greater than V2 inch, for example.These values are only intended to be exemplary and not any limitation onthe use or scope of the inventions disclosed herein. For automotiveapplications and others, the ported body 12 may comprise aluminum alloy,for example, but other metals may also be used as needed for particularapplications, such as machined or forged stainless steel. The conduitsherein may be made of stainless steel, such as 316 stainless steel, orother suitable metal for particular applications.

As noted, the body 12 is commonly understood as being a fittingcomponent that receives an end C1 of a conduit C. FIGS. 1-4 furthermoreillustrate an exemplary embodiment of an unthreaded mechanicalconnection for a conduit that embodies a single action or push toconnect conduit fitting.

The terms “complete connection” or “complete assembly” or “finalassembly” and derivatives thereof as used herein refer to joining thefitting components together to create a fluid tight seal and grip of thefitting assembly 10 with the conduit C. A pre-assembly or pre-assembledposition as used herein is one in which the fitting components may beloosely or snugly assembled before conduit insertion and such that aconduit end can be inserted into the loose assembly and retained thereinto form a completed connection. This pre-assembled position isexemplified in FIG. 1. We also refer to an initial or first connectionor make-up to refer to the first time that a fitting is assembled to acomplete assembled position such as illustrated in FIG. 2. A subsequentcomplete assembly or remake refers to any completed assembly after aprevious completed assembly was disassembled by conduit removal, whetherthat previous completed assembly was the initial completed assembly or alater completed assembly or remake of the fitting.

We also refer to the term “loosely assembled” and derivative forms torefer to an assembly of parts that are held together but have not beenfully assembled together to a position that effects conduit grip andseal and retention.

The various embodiments herein share a number of significant featuresthat individually and in various combinations or collectively provide arobust mechanical connection to a conduit end. The embodiments hereinare directed preferably to rigid conduits, such as metal tubing andpipe, as distinguished from flexible hose for example often with anon-metal conduit wall such as rubber or plastic. By rigid we mean thatthe conduit provides a sufficiently strong wall structure that allows aconduit gripping device such as, for example, a ferrule or ferrule-likedevice, to grip and optionally seal against an outer surface of theconduit, usually with a plastic deformation of a portion of the conduitand the gripping device. We do not use the word rigid to imply that theconduit cannot be bent or shaped as needed for a particular application.The term conduit is used in its broadest sense to include a metal stub,jacket, casing or sleeve and the like, and that may be used in an endfitting for a flexible non-metal hose.

A particular feature of interest is that the inventions provide anunthreaded mechanical connection to be made to a conduit end that doesnot need to be machined, formed or shaped other than the well known lowcost processes of end facing and deburring. The conduit end does notneed to be formed with recesses or external shapes. Thus, the inventionsmay be considered to provide a mechanical connection with a generallycylindrical or annular conduit shape having a smooth exterior surfacesuch as tube or pipe, although shaped conduits may be used if needed forparticular applications.

The body 12 may include a fluid bore 14 for fluid communication with theconduit C, or may simply be a blind port or cap. The body 12 includes afirst counterbore 16 that provides a shoulder or other surface againstwhich the conduit end wall C2 may bottom. However, it will be noted fromthe various embodiments herein that the fitting 10 does not require thatthe conduit C bottom against the shoulder 16 even when the fitting is ina completely assembled position (FIG. 2). As will be explained furtherhereinbelow, other exemplary techniques and structure may optionally beprovided to indicate and verify sufficient conduit insertion into thebody 12 for a completed assembly. In customary conduit fittings, it isusually desirable to have the conduit bottom against this shoulder 16,however, in the embodiments herein such bottoming may be less thancomplete because the conduit is provided with separate means forverifying that the conduit is fully inserted and bottoming is not neededfor effecting an adequate fluid-tight seal. Therefore, the shoulder 16is not a necessary feature of the body 12.

A second counterbore 18 is provided that has a somewhat larger diameterthan the first counterbore 16. A first seal element or member 20 may bedisposed in the recess of the second counterbore 18. The first sealelement 20 may be realized in many different forms and shapes, and inthe exemplary embodiment is preferably but not necessarily realized inthe form of an o-ring. The first seal element 20 may be made of anymaterial that is compatible with the system fluid contained by thefitting 10. For many gasses and liquids we use a fluorocarbon elastomerbut many other materials are available including plastics, polymers andsoft metal seals. When the conduit end C1 is sufficiently inserted so asto extend into the first counterbore 16, as shown for example in FIG. 2,the o-ring 20 is radially compressed between an outer surface C3 of theconduit and the cylindrical wall 22 of the second counterbore 18 toprovide a fluid-tight seal between the conduit end portion C1 and thebody 12 (note in the various figures herein that interference betweentwo surfaces may be represented by overlap of the parts rather thanshowing the compression that actually occurs).

The conduit end face C2 may be provided with an optional chamfer C4, forexample, a forty-five degree chamfer may be used as well as otherangles. The chamfer C4 facilitates inserting the metal conduit end intothe body 12 and past the o-ring seal 20 so as not to nick or otherwisedamage the softer seal.

A second and optional seal or backing ring 24 may be provided justoutboard of the first seal element 20. The first and second sealelements 20, 24 may be considered to form a seal mechanism although inmany applications a single seal element may be used and in othersperhaps additional seal elements may be used (see FIGS. 13 and 14 forexample). In this embodiment, we use the second seal element 24 todiminish extrusion of the first seal element 20, particularly when thefitting 10 is under system fluid pressure. We therefore select thesecond seal 24 material to be somewhat stiffer than the first seal 20,for example PEEK™, PTFE, PFA and Nylon™, but again many other materialsare available and well known and others may be later developed. Thebacking ring 24 may be a generally annular part with a generallycylindrical outer wall 26 and an inner diameter wall 28. In thisembodiment, the inner wall 28 includes a first portion 28 a that isgenerally cylindrical and closely received around the conduit outersurface C3, and a tapered portion 28 b that will be further describedbelow. When the conduit end C1 has been inserted to the fully assembledposition as shown in FIG. 2, the first portion 28 a of the innerdiameter wall 28 contacts the conduit wall so that the backing ring 24may be radially outwardly forced into compressive contact with thesecond counterbore wall 22. This compression provides excellentresistance to extrusion of the first seal 20 when the first seal 20 isexposed to system pressure. Note that the backing ring 24 may be splitas along kerf cut 30 to facilitate assembly of the rather stiff backingring 24 into the body and radial expansion outward when the conduit C isinserted. The radial compression of the second seal element 24 may alsoallow the second seal element 24 to provide a backup or secondary sealagainst fluid pressure should the first seal 20 allow fluid to bypass,particularly between the wall 22 and the first seal 20.

The body 12 may further include a reverse undercut in the form of anundercut 32, for example a tapered surface or wall 32, that may beformed between the second counterbore wall 22 and an outboardcylindrical wall 34 of the body 12. We have found that a taper angle ofabout forty-five degrees works well but other angles may be used asneeded. For example, we have found angles in the range of approximately30° to approximately 45° work well. The undercut 32 provides a taperedsocket 36 that receives a conduit retaining member or ring 38. Theconduit retaining ring 38 may be dimensioned to be at least partiallyreceived in or sit in the socket 36. The conduit retaining ring 38 maybe realized in many different forms including but not limited to a splitring, snap ring, scarf cut wire, single piece wire coil or otherradially expandable annular member, set of arcuate wire sections, ballsor gripper elements optionally attached to each other and so on. Theconduit retaining ring 38 preferably is radially expandable so that theretaining ring 38 may be displaced into an expanded space or volume suchas a recess, for example a tapered groove, during disassembly. Theretaining ring 38 preferably is also rigid or strong enough to becompressed about a surface, for example a surface of a ferrule or nut,to help retain the conduit against pressure blow-out, as described ingreater detail below.

The conduit retaining ring 38, in some embodiments, preferably may havean inside diameter that is sized to be rather closely received over aconduit gripping device 40 which will be further described hereinbelow.In other embodiments, the retaining ring 38 may be sized so as to engagewith a nut or other member of the fitting assembly. The retaining ring38 is referred to herein also as a conduit retaining ring but thisreference does not require direct contact between the retaining ring 38and the conduit, but rather a feature of the retaining ring is toprovide part of a structure that retains the fully inserted conduit inplace under conditions described in more detail below. We also refer tothe conduit retaining ring 38 as simply a retaining ring or member 38,or alternatively a conduit retainer or simply a retainer 38.

The conduit retaining ring 38 (also referred to herein as a retainingring or retaining device or retainer) preferably also has an outsidediameter that is sized to allow at least a portion of the retaining ring38 to be radially expanded into the adjacent larger diameter portion ofthe second counterbore 18 provided by the cylindrical wall 22. When soexpanded, the retaining ring 38 is disengaged from the conduit grippingdevice 40 (see FIG. 4). The smaller diameter or tapered socket 36 isdimensioned so as to engage the retaining ring 38 under certainconditions as further described below. The outboard cylindrical wall 34forms a bore or annular space (64, see FIG. 2) to accommodate adisassembly tool described hereinbelow.

The conduit gripping device or member 40 preferably may be realized inthe form of an annular body, for example, a ferrule or ferrule-likedevice that can be mechanically compressed, swaged or pre-swaged orotherwise attached onto the outer surface C3 of the conduit C.Preferably, the conduit gripping device 40 comprises a metal part, withthe metal comprising stainless steel as one example. We use the terms“compressed”, “swaged” and “pre-swaged” and derivatives thereofinterchangeably herein to refer to conduit gripping device attachment toa conduit using axially and/or radially compressive loads. As such, theconduit gripping device 40 may be compressed so that at least a portionof the conduit gripping device inside diameter of the inner walldecreases in diameter and becomes smaller than the outside diameter ofthe conduit, thus forming an interference or friction fit. Thisinterference or friction fit after the swaging or radial compression notonly retains the conduit gripping device 40 on the conduit forsubsequent make-up of the fitting, but also the conduit gripping device40 will not freely rotate on the conduit. In other embodiments herein, aconduit gripping device 40 is combined with a load retaining sleeve thatalso produces this interference fit and also reduces or eliminatesspring back of the conduit gripping device after the swaging step. Theload retaining sleeve may also have an interference or friction fit withthe conduit gripping device, and further these two parts may bepre-assembled as a cartridge or subassembly prior to being attached tothe conduit.

Many different conduit gripping device designs may be used as needed,but we prefer, as one example, a ferrule having a forward edge 42 thatwill bite into or penetrate the outer surface of the conduit C. Thisbiting or indentation action produces a shoulder 44 in the conduitsurface that facilitates the ferrule to have a significant conduit gripwhen the fitting 10 is under system pressure. Preferably, the ferrule 40will also exhibit a radially inward hinging action of a portion of theinterior wall of the ferrule that causes the ferrule to collet orotherwise be radially compressed and swaged against the conduit outerwall. The hinging preferably produces a convex profile to a portion ofthe inner wall of the ferrule, as distinguished from the less preferredradially outward bowing action of some ferrule designs. This actionprovides a colleting region 46 of strong swaging or compression of theferrule against the conduit surface so as to isolate the bite region 44and accompanying stress riser near the front of the ferrule 40 fromconduit vibration, shock and other stresses. The features of a hingingand colleting ferrule are fully described in U.S. Pat. Nos. 6,629,708;7,100,949; 7,240,929; 7,367,595; 7,614,668; 7,699,358 and 7,762,595, theentire disclosures of which are fully incorporated herein by reference.

Although we prefer that the ferrule 40 exhibit the desired hinging andcolleting effect to provide excellent conduit grip and optional sealunder pressure, such a ferrule may not be needed in all applications. Abenefit of using a ferrule that strongly grips and optionally sealsagainst the conduit C is that the ferrule may provide a good back upseal to the o-ring seal along the conduit surface C3. The colleting orswaging action provides excellent isolation of the bite region 44 fromconduit vibration and shock which may commonly occur in someapplications such as automotive.

The ferrule 40 may also provide a means or mechanism by which theconduit C is captured and retained in the body 12. The ferrule 40 may beprovided with an outer tapered surface or wall 48 and rearward extendingflange 50 that provide a ferrule outer socket, notch or recess 52 thatreceives the retaining ring 38 when the conduit C has been inserted intothe body 12. In other alternatives, the ferrule tapered wall 48 may becontoured rather than just being tapered or conical, for example, theferrule tapered wall 48 may be contoured such as with a convex surface,a concave surface or other shape as needed.

Many different techniques may be used to attach the ferrule 40 to theconduit C. In a preferred method, a swaging tool may be used. Swagingtools are commonly used in the art to install one or more ferrules on aconduit end before assembly of a fitting. This is particularly commonwith larger ferrules and conduit outside diameters. With the presentinventions, however, we use swaging of the ferrule so as to provideexcellent conduit grip or retention on the conduit C, and may alsoprovide vibration resistance or isolation from the bite, while at thesame time providing a device that cooperates with the retaining ring 38to securely hold the conduit C in the body 12. A suitable swaging toolis model AHSU, a pneumatic driven hydraulic swaging unit available fromSwagelok Company, Solon, Ohio. However, other apparatus and methods maybe used as needed to attach the ferrule 40 to the conduit C. By swagingthe ferrule 40 onto the conduit prior to conduit insertion, a simplesingle action push to connect fitting is provided for rigid conduitswhich does not require any additional torque or tightening action of thefitting as is used in traditional flareless tube fittings. Rather,fitting assembly is completed by simply inserting the conduit end C1into the body 12 until the retaining ring 38 snaps over the ferrule 40and settles into the ferrule outer socket 52. Thus, fitting assembly iscompleted by a single motion of insertion in a single direction and formany designs may be but need not be accomplished by hand. In someembodiments, the single motion may be accomplished with a tool such as apiston.

FIG. 1 illustrates the conduit fitting assembly 10 in a looselyassembled position preparatory to inserting the conduit end C1. Thefirst and second seal elements 20, 24 may be first inserted into thebody 12 along with the retaining ring 38. The ferrule 40 is swaged ontothe conduit C prior to the conduit being inserted for complete assembly.

In FIG. 2 the conduit C has been axially pushed into the assembly 10until the retaining ring 38 spreads outward and over the ferrule 40,particularly the tapered surface 48 of the ferrule, and snaps into theferrule recess 52. This may be accompanied by an audible click ortactile sensation of resistance to further insertion of the conduit C asan intrinsic gauge so that the assembler knows that the conduit has beenproperly inserted to this position. The radially enlarged recess portion36 of the body 12 accommodates radial expansion of the retaining ring 38as it slides over the ferrule 40. The conduit may be pushed in with theretaining ring 38 sliding along the tapered outer surface 52 of theferrule 40 until the retaining ring 38 axially aligns with the ferrulerecess 52, at which point the retaining ring snaps into position asshown in FIG. 2. Note that in the position of FIG. 2 the seal mechanism20, 24 is fully compressed into scaling engagement with the body wall 22and the conduit outer surface C3.

Also note in FIG. 2 that when the conduit C has been fully inserted, aforward portion of the ferrule 40, and notably the front edge 42 andbite region 44, and optionally a portion of the ferrule outer recess 52,may be compressed between the backing ring 24 and the conduit C. Thus,the backing ring 24 may be used to help maintain a strong collet andswage compressive force, and thus strong conduit grip, by the ferrule40. This may be further facilitated by providing the tapered portion 28b of the retaining ring 24 at a suitable angle to help further compressthe ferrule 40 against the conduit.

After the conduit C has been inserted into the body 12 as in FIG. 2, theconduit end is captured by the retaining ring 38 because the retainingring 38 is captured between the tapered surface 32 and the ferrule outerrecess 52, such that the retaining ring 38 interferes with the ferruletapered back wall 48 should an attempt be made to axially withdraw theconduit. At this point and for this embodiment, as an example, theconduit C can only be removed from the nut 14 by use of a tool(described hereinbelow). Although we illustrate a particular shape forthe ferrule 40 to operate with the retaining ring 38, this is but oneexample. The ferrule 40 and retaining ring 38 may be designed with manydifferent shapes to facilitate their interaction to retain the conduit Cin the body 12 to form a completed connection.

FIG. 3 illustrates the conduit fitting assembly 10 under systempressure, whereas FIG. 2 illustrates the fitting assembly at no pressureor very low pressure. Under pressure as in FIG. 3, the first seal 20tends to be pushed axially outboard on the conduit outer surface againstthe backing ring 24. This action will tend to increase the colleting orcompression of the backing ring 24 against the tapered outer surface 52of the ferrule, thus further increasing the grip and optional sealfunctions of the ferrule 40 against the conduit C. Also note that underpressure the conduit C will also tend to be forced axially away from theshoulder 16, but this action will cause further axial and radialcompression of the retaining ring 38 between the tapered surface 32 andthe tapered wall 48 of the ferrule 40, which may also further increasethe colleting and swaging of the ferrule 40 against the conduit. Theshape of the retaining ring 38 and the tapered wall 48 of the ferrulemay be selected to enhance this result as needed. The ferrule 40 may bemade of a suitable material including a material different from thematerial of the conduit, to exhibit good wear resistance when thefitting is under pressure and the ferrule 40 is in contact with theretaining ring 38. For example, the ferrule 40 may be case hardened orwork hardened metal. Under system pressure, even if there are slightaxial movements or substantial loads applied to the conduit and theseals 20, 24, the seal 20 maintains a fluid tight seal against theconduit and the body wall 22.

An assembler can verify that the conduit is properly inserted withdifferent intrinsic gauge methods. One is the audible click when theretaining ring 38 snaps into position. The assembler will also note asignificant resistance to further insertion of the conduit, as well asthe inability to pull the conduit back out. Other visual markings orindications may be provided as needed to provide visual confirmationthat the conduit is fully seated, such as, for example, a scribe mark onthe conduit that becomes hidden by the end of the body 12 after theconduit is fully inserted. Many other intrinsic gauge techniques may beused and will be readily apparent to those skilled in the art.

Disassembly of the fitting 10 may be quickly and easily accomplished byuse of a tool 60. With reference to FIG. 4, the tool 60 includes aretaining ring release portion or extension 62 which has been insertedthrough an annular space 64 (FIG. 2) between the conduit outer surfaceC3 and the outer body bore 34. The tool 60 may have any configurationthat will allow insertion of the extension 62, such as for example acylinder 66 or prongs or legs to extend into the fitting to engage theretaining ring 38. The tool extension 62 is inserted so as to expand theretaining ring 38 into the larger bore formed by the cylindrical wall 22so that the retaining ring 38 has an expanded diameter that is largeenough to allow the ferrule 40 to be axially withdrawn past theretaining ring. This allows the conduit C and the attached ferrule 40 tobe withdrawn from the fitting assembly, preferably after system pressurehas been released. The tool 60 may be made of any metal or non-metalmaterial and simply needs to be stiff enough to spread the retainingring 38 and prevent the retaining ring 38 from being pulled backward(outboard) when the conduit C and ferrule 40 are axially withdrawn fromthe fitting assembly 10. The tool may be split or scarf cut to allowwrap-around about the conduit C before insertion into the annular space64. The tool 60 may include an enlarged gripping portion 68 tofacilitate manual insertion into the fitting assembly 10.

In accordance with this and other embodiment of the inventions then, thebenefits of an energized ferrule including conduit grip and optionalseal under pressure and optional but preferred vibration isolation ofthe bite region from conduit stress and vibration are utilized torealize a high pressure single action push to connect fitting assembly.

FIG. 5-7 illustrate another embodiment of a fitting assembly 70. In thisembodiment, a body 72, first seal 74 and second seal 76 may be used andmay be the same as in the first embodiment of the parts 12, 20 and 24 ofthe first embodiment and therefore will not be described again. The sealmembers 74 and 76 are received in a bore 75. A ferrule assembly or set78 is provided which is preferably swaged onto the conduit C prior toinsertion of the conduit into the body 72 (FIG. 5 shows such apre-swaged arrangement prior to complete insertion of the conduit intothe body 12). The ferrule assembly 78 may include a conduit gripping andoptional sealing ferrule 80, and a load retaining cap or sleeve 82. Theferrule 80 and the sleeve 82 may be a cartridge assembly meaning thatthese two components may be held together as a separate subassembly 78prior to installing the ferrule assembly onto the conduit C. Forexample, the sleeve and ferrule may be secured together by a press fit,mechanical snap together, or an adhesive or other means as needed.

The exemplary ferrule 80 may include a tapered exterior surface 81 thatcams against or otherwise engages a tapered interior surface 83 of thesleeve 82. When the ferrule 80 and load retaining sleeve 82 are axiallyforced together, the ferrule 80 is radially constrained and aninterference or friction fit is produced to thereby hold the ferrule 80and the sleeve 82 together as a pre-assembly or cartridge.

The ferrule assembly or cartridge 78 can be attached to the conduit by aswaging tool as noted hereinabove or by any other convenient means. Forexample, a radial compressive force may be applied about a portion orall of the ferrule assembly 78 to swage the ferrule assembly 78 onto theconduit. The load retaining sleeve 82 operates to prevent orsubstantially limit spring back of the swaged ferrule 80.

The swaging or radial compression results in the ferrule 80 having aninside diameter that is smaller than the un-stressed outside diameter ofthe conduit, thus providing an interference fit style attachment of theferrule on the conduit.

The ferrule set 78 may be attached to the conduit by a swaging tool asnoted hereinabove or by any other convenient means. For a push toconnect fitting, the sleeve 82 preferably remains with the ferrule 80after swaging and may be used to reduce spring back of the ferrule 80,particularly the front portion 80 a of the ferrule that bites into theconduit outer surface. In a traditional non-push to connect fitting,this spring back can occur for energized ferrules that have beenpre-swaged onto a conduit after the swaging force is removed, prior tocompleting a pull-up of the fitting. But for this embodiment of our pushto connect fitting, there is no need for a second ferrule or taperedsurface to complete the connection as in a traditional fitting.Therefore, we use the load retaining sleeve 82 for our push to connectfitting to radially constrain the ferrule 80 and therefore maintain thepre-load applied to the ferrule 80 during swaging and prevent or reducetendency for the ferrule to spring back. This may significantly improvethe conduit grip and optional seal functions of the ferrule 80 bymaintaining excellent bite and colleting for conduit grip under pressureand vibration isolation.

It will be noted that because this embodiment uses the load retainingsleeve 82, the second seal member 76 does not need to engage with theferrule set 78, therefore the second seal may have a substantiallycylindrical interior wall 77, with an optional chamfer 77 a provided toprevent damage when the conduit C is passed therethrough.

A nut 84 may be provided which cooperates with a retaining ring 86 tosecure and retain the conduit C in the body 72 after complete assembly.The nut 84 may be used conveniently to help insert the conduit into thebody 72 and for this purpose may include a back flange or handle 88. Thenut 84 also may include a forward nose 90 having a tapered outer surface92 and a recess or groove 94 formed by a shoulder 96. The nut 84 may beunthreaded so as to be used to effect a single action push to connectoperation.

The body 72 may include a tapered recess 98 that allows radial expansionof the retaining ring 86. With reference to FIG. 6, when the conduit Cand nut 84 are inserted into the body 72, the retaining ring 86 radiallyexpands into the larger diameter portion of the body tapered recess 98as the ring 86 slides over the tapered surface 92 of the nut 84. Uponcomplete assembly, the retaining ring 86 moves or snaps into the nutgroove 94, which is the position illustrated in FIG. 6. Note that theretaining ring 86 is axially captured between the nut groove 94 and thetapered surface or wall 100 of the body tapered recess 98. Thisinterference prevents axial withdrawal of the conduit C from the body 72without the use of a tool.

An optional bearing or gimbal 102 may be provided between the back end78 a of the ferrule set 78 and an inner shoulder 104 of the nut 84. Thisbearing 102 preferably is loosely installed on the conduit C. Thebearing 102 may have any geometry that cooperates with the profile ofthe engaging surface 104 of the nut so as to allow radial pivot orflexing about the bearing 102, functionally somewhat in the nature of auniversal joint. The bearing 102 may be used to bear the axial load ofthe conduit C and the ferrule 80 particularly when the fitting 70 isunder system fluid pressure, in the nature of a thrust bearing. Thebearing 102 may also provide a radial flexure or pivot region 106 forthe conduit particularly when the conduit C is subjected to rotary orplanar vibration or movement. This pivot region 106 thus may be axiallyspaced or positioned from the bite 80 a and/or associated stress areasin the conduit produced by the swaged conduit gripping device to isolatethe ferrule bite 80 a and/or stress area from rotary flex, vibration ormovement of the conduit as well as other fatigue inducing disturbancesin the conduit, thus enhancing the vibration isolation effect of thecolleting and swaging 80 b by the ferrule 80. The bearing 102 preferablyis designed with a small outer diameter and small surface area. Thebearing 102 may be a separate discrete component as illustrated in FIGS.5-7 or may be integrally formed as part of the ferrule 80 or the nut 84(see FIG. 12 for example). It should be noted that the retaining ring 38in the first embodiment may be designed to also provide this bearingeffect by virtue of the direct contact between the back portion of theferrule 40 and the tapered wall 32.

For disassembly, as illustrated in FIG. 7, a tool 108 may be used thatincludes a sleeve or extension 110. The sleeve 110 may be insertedthrough an annular space 112 (FIG. 6) between the nut 84 and the body72. When the tool 108 is pushed in, the sleeve pushes the retaining ring86 into the radially larger portion of the body tapered recess 98, thusallowing the nut 84 and conduit C to be axially withdrawn from the body72.

We note at this point that a ferrule set such as for example used in thesecond embodiment may alternatively also be incorporated into the firstembodiment. This would remove the use of the second seal or backing ring24 from having to engage with the ferrule 40.

FIG. 8 illustrates another embodiment of a push to connect conduitfitting assembly 120. In this embodiment, a ferrule set 122 is used asin the second embodiment, however, the ferrule set 122 is modifiedsomewhat. The ferrule set 122 includes a ferrule 124 and a sleeve 126which may be a cartridge type preassembly before being attached to theconduit C. The ferrule set 122 may then be swaged or otherwise attachedto the conduit C prior to the conduit C being inserted into the body128. It will be noted that this embodiment illustrates an example of abody that is in the form of a plug having a closed second end. Theferrule 124 includes a rearward flange portion 130 which has an annulargroove or recess 132 formed in an outer surface 134 thereof This recess132 may be configured as needed to receive portions of the retainingring 136 when the conduit C is inserted into the body 128. A first sealmember 138 is provided as in the first two embodiments to provide afluid tight seal between the body 128 and the conduit C. An optionalanti-extrusion backing ring (not shown) may be used as needed, as in thefirst two embodiments. However, in the embodiment of FIGS. 8-11 we donot use a backing ring because the sleeve 126 may be dimensioned toprovide a small gap with the body 128 so as to minimize the extrusiongap (see FIG. 10).

The retaining ring 136 in this example may be carried or integrated withan optional positioning sleeve 140. During assembly, the positioningsleeve 140 and retaining ring 136 may be seated in the body 128 so thatthe retaining ring 136 is axially aligned with a tapered recess 142 inthe body. The retaining ring 136 and positioning sleeve 140 may also berealized as a subassembly prior to installation into the body. Inalternative embodiments, the positioning sleeve may be a separatecomponent that is used to move the retaining ring 136 into the taperedrecess 142 during disassembly. As shown in FIG. 9, the positioningsleeve 140 may include one or more arcuate openings or slots 144 in thecylindrical wall 146 of the sleeve. These openings 144 receive theretaining ring 136 to hold the ring to the sleeve, while at the sametime permitting the retaining ring 136 to be radially expanded duringassembly and disassembly of the fitting 120. In the embodiment of FIG.9, there are two openings 144 which may be diametrically opposed to eachother. The greater the arcuate length, the more inside diameter surfacearea of the retaining ring 136 is available to engage the ferrule recess132. In order for the retaining ring 136 to be received in the ferrulerecess 132, the lands 150 between the arcuate openings 144 may have aminor outside diameter that is somewhat smaller than the major diameterof the cylindrical wall 146 of the sleeve. This allows correspondingarcuate portions of an inner surface area of the retaining ring 136 tobe received in the ferrule recess 132, as best illustrated in FIG. 10.The entire outer diameter surface area of the retaining ring 132 isavailable to engage the tapered wall 148 body tapered recess 142. Theretaining ring 132 may be a split ring to facilitate radial expansioninto the tapered recess 142 as needed.

With reference to FIG. 10, in the fully assembled position the seal 138is radially compressed between the body 128 and the outer surface of thecylindrical conduit C. The forward end of the ferrule sleeve 126 mayhelp to restrain the seal 138 against extrusion under pressure or abacking ring may be used. As the conduit C is pushed into the body 128,the assembler may hear an audible click when the retaining ring 136snaps into the ferrule recess 132. The ferrule 124 may also be designed,for example, with an axial length such that the back end 124 a of theferrule becomes flush with or recessed into the body, as illustrated inFIG. 10. This is another optional technique for intrinsic gauging thatthe fitting has been completely assembled. If the conduit C is pulledbackward or forced backward under system pressure, the positioningsleeve 140 also moves back until the retaining ring 136 engages thetapered wall 148 of the body recess 142. This prevents the conduit Cfrom being axially withdrawn from the body 128 without changing theposition of the positioning sleeve 140.

For disassembly and as illustrated in FIG. 11, after system pressure isreleased the positioning sleeve 140 may be axially pushed forward untilthe retaining ring 136 is aligned with the radially enlarged portion ofthe tapered recess 142. This allows the retaining ring 136 to expandradially outwardly when the conduit C and the attached ferrule set 122are axially withdrawn from the body 128.

We thus disclose and claim a fitting assembly for making a mechanicalconnection to a rigid cylindrical conduit by a single action push toconnect method. This mechanical connection may include the use of aconduit gripping and seal device that hinges and collets onto theconduit, before the push to connect action, during a swaging or othercompression operation to provide excellent conduit grip, optional seal,and vibration isolation. A primary seal may be provided by a soft sealsuch as an o-ring, with use of an optional backing ring or rings. Insome embodiments, a bearing may be provided to further isolate conduitvibration and fatigue effects from the ferrule bite in the conduit. Alsoin some embodiments a sleeve may be used as part of a ferrule set orcartridge to retain swage pre-load on the ferrule after the swagingoperation is completed. The push to connect action may be a singleaction in the sense that for the final complete connection step, asingle direction of engagement to push the conduit into the fitting toachieve seal and retention may be used, and the push to connect actionmay in many cases be performed manually. Disassembly may be realizedwith the use of a tool that may be assembled with the fitting orseparately used after fitting assembly.

With reference to FIGS. 12 and 13 (and FIGS. 5-7) we illustratealternative embodiments, some of which clearly apply to all theembodiments herein. In FIG. 12, for example, we start with the basicconfiguration of the embodiment of FIGS. 5-7 but also show the use oftwo backing rings 152 a and 152 b. The backing ring 152 b that isfurthest axially from the first seal 74 may be made of a somewhat hardermaterial than the first backing ring 152 a to provide furtheranti-extrusion resistance to the seal assembly which includes the firstseal 74 and the two backing rings 152 a and 152 b. The use of extrabacking rings or seal members may be provided in the other embodimentsherein as well. Also provided is an inward constriction 154 formed inthe bore 75. This constriction may be used to prevent the seal members74, 152 a and 152 b from accidentally being withdrawn from the body 72when the conduit C is axially withdrawn after a completed assembly. Thisconstriction may be used in the other embodiments as well.

In FIG. 12 we also show the use of a gimbal or bearing 156 integrallyformed with the nut 84, in lieu of the discrete bearing 102 (FIG. 5).The use of a machined gimbal or bearing eliminates a separate componentof the fitting and may be shaped as needed to effect the bearingfunction. In this example, the integral bearing 156 is machined into thenut 84. Also note that the nut 84 back end has been axially truncated ascompared to the embodiment of FIG. 5. When the nut 84 is fully insertedinto the body for a completed assembly in which the retaining ring 86snaps into the recess 94 (FIG. 5) of the nut, the back end 84 a of thenut may be flush with or slightly recessed into the body 72 thusproviding a visually perceptible intrinsic gauging feature to verifycomplete assembly.

The FIG. 13 embodiment may include the arrangement of FIG. 12 exceptthat a ferrule like bearing member or gimbal 158 is used rather than theintegral bearing 156. We have found that a ferrule like member such asused in the FIG. 1 embodiment also provides the desired gimbal orbearing function, and the shape of the ferrule may be controlled toproduce the desired rotary flexing and vibration isolation effects.

With reference to FIG. 14, we illustrate another embodiment of a push toconnect fitting 200 that provides a single action mechanical connectionfor a conduit end. This embodiment shares features of the firstembodiment (FIGS. 1-4) and the embodiments of FIGS. 12 and 13, andtherefore those descriptions need not be repeated in their entirety. Inthis embodiment, a single ferrule 202 is attached to the conduit endportion C1 such as by a swaging operation for example, prior to theconduit end C1 being inserted into the body 204. In contrast to thefirst embodiment of FIG. 1, however, a nut 206 cooperates with theretaining ring 38 to hold the fitting together and to retain the conduitend C1 with the body 204. The nut 206 may be but need not be similar tothe nut 84 in the embodiment of FIG. 12, for example. Although notshown, the nut 206 may optionally include the integral gimbal 156 (FIG.12). The push to connect fitting 200 may further include a sealmechanism such as a first seal 20 and backing ring 24 or an alternativeseal mechanism may be used as needed. The body 204 may include a taperedrecess 208 that cooperates with the retaining ring 38 in a manner asdescribed with reference to FIG. 12.

The single action push to connect fitting 200 is assembled by slippingthe nut 206 onto the conduit C1 behind the attached ferrule 202 and thenaxially inserting the conduit end C1 into the body 204 until theretaining ring 38 engages with a surface of a nut recess 208, such as atapered surface 210. The retaining ring 38 is captured between the nutrecess tapered surface 210 and a surface of the tapered recess 208 toprevent the conduit end from being axially separated from the body 204until the retaining ring 38 is displaced into the enlarged volume of thetapered recess 208. The fitting thus provides an unthreaded mechanicalconnection between the conduit end and the body 204 using a singleaction push to connect method.

FIG. 15 illustrates another alternative embodiment that may be similarto the embodiment of FIG. 14 so that such description need not berepeated. The FIG. 15 embodiment differs from the FIG. 14 embodiment inthat a ferrule like bearing or gimbal 220 may be optionally used. Thisaspect may be similar to the above description with respect to thebearing 158 of the FIG. 13 embodiment herein.

The inventive aspects have been described with reference to theexemplary embodiments. Modification and alterations will occur to othersupon a reading and understanding of this specification. It is intendedto include all such modifications and alterations insofar as they comewithin the scope of the appended claims or the equivalents thereof

We claim:
 1. A push to connect fitting, comprising: a body member havinga counterbore, an enlarged recess extending radially outward and axiallyoutboard of the counterbore, and a reverse undercut extending radiallyinward and axially outboard of the enlarged recess; a conduit comprisinga first end that can be axially inserted into the counterbore of thebody member; a conduit attachment subassembly assembled with theconduit, the conduit attachment subassembly comprising a conduitgripping device attached to an exterior surface of the conduit and aload retaining sleeve installed onto the conduit, the load retainingsleeve including an inner radial surface that surrounds and engages anouter radial surface of the conduit gripping device to maintaincompressive load on the conduit gripping device after the conduitgripping device has been attached to the exterior surface of theconduit; and a retainer installed in the body member and capturedbetween the counterbore and the reverse undercut, wherein the retainerengages a portion of the conduit attachment subassembly to retain theconduit in place within the body member when the conduit, with theconduit attachment subassembly, is fully inserted into the body member;wherein the body member comprises a tapered groove into which theretainer can expand to allow axial separation of the conduit and thebody member.
 2. The push to connect fitting of claim 1 wherein theconduit gripping device comprises a ferrule that is under compressionagainst the exterior surface of the conduit so that at least a portionof the conduit gripping device inside diameter is smaller than anoutside diameter of the conduit.
 3. The push to connect fitting of claim1 comprising a seal disposed on the exterior surface of the conduit. 4.The push to connect fitting of claim 1 wherein the retainer engages theportion of the conduit attachment subassembly when the conduit has beenfully inserted into the body member.
 5. The push to connect fitting ofclaim 4 wherein the retainer comprises a radially expandable metal ring.6. The push to connect fitting of claim 1 wherein the body membercomprises a tapered surface, the retainer being captured between asurface of the conduit attachment subassembly and the tapered surface ofthe body member when the conduit has been fully inserted into the bodymember.
 7. The push to connect fitting of claim 1, comprising a sealdisposed in the body member and that seals against the exterior surfaceof the conduit when the conduit has been fully inserted into the bodymember.
 8. The push to connect fitting of claim 7, wherein the sealcomprises an O-ring.
 9. The push to connect fitting of claim 7, furthercomprising a backing ring disposed in the body member in engagement withthe seal.
 10. The push to connect fitting of claim 1, wherein theconduit comprises stainless steel and the conduit gripping devicecomprises stainless steel.
 11. The push to connect fitting of claim 1,wherein the portion of the conduit attachment subassembly is defined bythe conduit gripping device.
 12. The push to connect fitting of claim 1,wherein the exterior surface of the conduit and an interior edge of thereverse undercut define an annular space that aligns with a portion ofthe retainer for engagement of the retainer by insertion of a toolthrough the annular space.
 13. The push to connect fitting of claim 1,wherein the retainer is captured between the counterbore and the reverseundercut of the body member when the conduit, with the conduitattachment subassembly, is axially withdrawn from the body member.
 14. Apush to connect fitting, comprising: a body member having a counterbore,an enlarged recess extending radially outward and axially outboard ofthe counterbore, and a reverse undercut extending radially inward andaxially outboard of the enlarged recess; a conduit comprising a firstend that can be axially inserted into the counterbore of the bodymember; a conduit attachment subassembly assembled with the conduit, theconduit attachment subassembly comprising a conduit gripping deviceattached to an exterior surface of the conduit and a load retainingsleeve installed onto the conduit, the load retaining sleeve includingan inner radial surface that surrounds and engages an outer radialsurface of the conduit gripping device to maintain compressive load onthe conduit gripping device after the conduit gripping device has beenattached to the exterior surface of the conduit; and a retainerinstalled in the body member and captured between the counterbore andthe reverse undercut, wherein the retainer engages a portion of theconduit attachment subassembly to retain the conduit in place within thebody member when the conduit, with the conduit attachment subassembly,is fully inserted into the body member; wherein when the conduit isfully inserted into the body member, an end face of the conduit engagesan internal shoulder in the body member.
 15. The push to connect fittingof claim 14, wherein the body member comprises a tapered groove intowhich the retainer can expand to allow axial separation of the conduitand the body member.
 16. A push to connect fitting, comprising: a bodymember having a counterbore, an enlarged recess extending radiallyoutward and axially outboard of the counterbore, and a reverse undercutextending radially inward and axially outboard of the enlarged recess; aconduit comprising a first end that can be axially inserted into thecounterbore of the body member; a conduit attachment subassemblyassembled with the conduit, the conduit attachment subassemblycomprising a conduit gripping device attached to an exterior surface ofthe conduit and a load retaining sleeve installed onto the conduit, theload retaining sleeve including an interior surface that engages anexterior surface of the conduit gripping device to maintain compressiveload on the conduit gripping device after the conduit gripping devicehas been attached to the exterior surface of the conduit; and a retainerinstalled in the body member and captured between the counterbore andthe reverse undercut, wherein the retainer engages a portion of theconduit attachment subassembly to retain the conduit in place within thebody member when the conduit, with the conduit attachment subassembly,is fully inserted into the body member; wherein the conduit attachmentsubassembly further comprises a nut having an inboard end receivable inthe body member.
 17. The push to connect fitting of claim 16, whereinthe portion of the conduit attachment subassembly is defined by the nut.18. The push to connect fitting of claim 16, wherein the inboard endportion of the nut extends over a portion of the conduit grippingdevice.
 19. The push to connect fitting of claim 16, wherein the inboardend portion of the nut extends over a portion of the load retainingsleeve.
 20. A push to connect fitting, comprising: a body member havinga counterbore, an enlarged recess extending radially outward and axiallyoutboard of the counterbore, and a reverse undercut extending radiallyinward and axially outboard of the enlarged recess; a conduit comprisinga first end that can be axially inserted into the counterbore of thebody member; a conduit attachment subassembly assembled with theconduit, the conduit attachment subassembly comprising a conduitgripping device attached to an exterior surface of the conduit and aload retaining sleeve installed onto the conduit, the load retainingsleeve including an interior surface that engages an exterior surface ofthe conduit gripping device to maintain compressive load on the conduitgripping device after the conduit gripping device has been attached tothe exterior surface of the conduit; and a retainer installed in thebody member and captured between the counterbore and the reverseundercut, wherein the retainer engages a portion of the conduitattachment subassembly to retain the conduit in place within the bodymember when the conduit, with the conduit attachment subassembly, isfully inserted into the body member; wherein the exterior surface of theconduit gripping device and the interior surface of the load retainingsleeve are tapered for camming engagement.